Devices and systems for surgical retraction

ABSTRACT

Retractor blade assemblies, retractors, kits, and methods of using the same. The retractor blade assembly may include a retractor blade, a pedicle screw, and a shim that connects the pedicle screw to the retractor blade. The retractor blade may have a proximal end configured to engage a retractor body and a distal end configured to retract soft tissue. The pedicle screw may have a head portion removably connected to the distal end of the retractor blade and a shaft portion configured to engage the pedicle of a vertebra. The shim couples the pedicle screw to the retractor blade. For example, the shim may include an extension portion configured to engage the retractor blade and a connection portion configured to receive and temporarily lock the pedicle screw to the retractor blade.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 14/828,695 filed on Aug. 18, 2015, which isincorporated in its entirety herein.

FIELD OF THE INVENTION

The present disclosure generally relates to devices and systems forperforming pedicle-based surgical retraction and/or distraction andmethods of use thereof.

BACKGROUND OF THE INVENTION

Many types of spinal irregularities can cause pain, limit range ofmotion, or injure the nervous system within the spinal column. Theseirregularities can result from, without limitation, trauma, tumor, discdegeneration, and disease. Often, these irregularities are treatedthrough a surgical procedure that may include, for example, immobilizinga portion of the spine. These treatments may involve, for example,replacing a damaged disc with an intervertebral implant and/or securingthe adjacent vertebrae, for example, with a combination of screws androds. For correction of a collapsed disc causing impingement of one ormore nerve roots, for example, the disc space may be restored back to ornear its original height and the collapsed disc may be replaced with adevice and/or bone graft material.

In order to perform these procedures, a surgical opening is created, anda device such as a retractor may be used to enlarge the opening andfacilitate access to the surgical site. The retractor may typicallyinclude one or more blades that can be adjusted to establish, provide,and/or maintain an appropriate opening that minimizes trauma tosurrounding tissue. A distractor may also be used to distract the discspace, for example, by placing a portion of the distractor betweenvertebral bodies or by using adjacent level pedicle screws.

By using a pedicle-based retraction system, the retractor can performthe functions of both a retractor and a distractor. For example, theblades may provide for soft tissue retraction, and the pedicle screwsmay be configured to simultaneously facilitate distraction of the discspace. There is a need, however, for improved retractors which providepedicle-based distraction and soft tissue retraction. For example,pedicle-based retractors require a secure connection between the bladeand the pedicle screw. It is also desirable to have a mechanism toattach the blades to the screws after the screws have already beenaffixed to bone. Preferably, there is a minimal amount of tissuedisruption when connecting the blades to the screws intra-operatively.

SUMMARY OF THE INVENTION

To meet this and other needs, devices, systems, and methods forperforming pedicle-based surgical retraction are provided. Inparticular, the pedicle-based retractors are provided with speciallydesigned connections between the pedicle screw and blade, which create asecure reversible connection between the pedicle screw and the retractorblade. After the screw is implanted in the bone, the blade may beattached to the screw in a manner to minimize the amount of tissuedisruption at the surgical site.

According to one embodiment, a retractor blade assembly includes aretractor blade, a screw, and a shim which connects the screw to theretractor blade. The retractor blade may have a proximal end configuredto engage a retractor body and a distal end configured to retract softtissue. The screw may have a head portion removably connectable to thedistal end of the retractor blade and a shaft portion configured toengage bone. The shim may have an extension portion configured to engagethe retractor blade and a connection portion configured to receive atleast a portion of the screw. The connection portion may be movable froman unlocked position to a locked position for retaining the screw withinthe shim.

According to another embodiment, a retractor assembly includes aretractor body, at least one retractor blade, at least one pediclescrew, and at least one shim that connects the pedicle screw to theretractor blade. The retractor blade may have a proximal end configuredto engage the retractor body and a distal end configured to retract softtissue. The pedicle screw may have a head portion removably connectableto the distal end of the retractor blade and a shaft portion configuredto engage bone. The shim may have an extension portion, an outerspherical portion, and an inner spherical portion rotatably receivedwithin the outer spherical portion. The extension portion may beconfigured to engage the retractor blade and the inner spherical portionmay be configured to receive the head portion of the pedicle screw. Theinner spherical portion rotates from an unlocked position to a lockedposition for retaining the head portion of the pedicle screw within theshim.

The retractor blade assembly and/or the retractor assembly may includeone or more of the following attributes: the extension portion mayinclude at least one rail configured to slidably engage at least onecorresponding rail on the retractor blade; the extension portion mayinclude at least one edge configured to surround one or both endportions of the retractor blade; the retractor blade may include agenerally curved inner portion having one or more grooves defined alongat least a portion of the at least one retractor blade, the one or moregrooves configured to slidably engage one or more corresponding tonguesof the extension portion of the at least one shim; the shim may includean elongated slot extending longitudinally along a length of the shim;the connection portion may be configured to rotate relative to theretractor blade; the connection portion may include at least a partialring configured to at least partially surround the head portion of thescrew; a top portion of the inner spherical portion may extend throughan opening in the outer spherical portion, and the top portion may beconfigured to be engaged by a driver in order to rotate the innerspherical portion from the unlocked position to the locked position; thescrew may be side-loaded into the shim; the outer spherical portion andthe inner spherical portion may each include an opening that, whenaligned, allow the pedicle screw to be side-loaded into the shim; thepedicle screw may be configured to polyaxially rotate in the shim; oneor more locks may be positioned along one or both outer edges of theretractor blade to prevent the shim from sliding off the retractorblade; and the driver may include at least one track configured toengage the at least one rail on the extension portion of the shim.

According to yet another embodiment, a method of retracting anddistracting a disc space between first and second vertebrae may include:(a) connecting a driver to a first shim; (b) attaching a first pediclescrew to the first shim by side loading the first pedicle screw into thefirst shim and locking the first pedicle screw to the first shim; (c)attaching the first pedicle screw to a pedicle of the first vertebra;(d) sliding a first retractor blade having a proximal portion and adistal portion down the driver and onto the first shim such that thedistal portion of the first retractor blade connects to the first shim;(e) removing the driver; and (f) connecting a retractor body to theproximal portion of the first retractor blade. In addition, the methodmay optionally include: (g) connecting the driver to a second shim; (h)attaching a second pedicle screw to the second shim by side loading thesecond pedicle screw into the second shim and locking the second pediclescrew to the second shim; (i) attaching the second pedicle screw to apedicle of the second vertebra; (j) sliding a second retractor bladehaving a proximal portion and a distal portion down the driver and ontothe second shim such that the distal portion of the second retractorblade connects to the second shim; (k) removing the driver; (l)connecting the retractor body to the proximal portion of the secondretractor blade; and (m) retracting and distracting the disc space usingthe first and second retractor blades and the first and second pediclescrews, respectively.

According to yet another embodiment, a kit may include a pluralityshims, blades, and/or screws of different sizes and differentconfigurations. The kit may further include one or more retractor bodiesand attachment mechanisms, such as surgical arms, table arms, or thelike. In addition, the kit may include one or more devices suitable forinstalling and/or removing the retractor blade assemblies describedherein, such as insertion devices or drivers; one or more removaldevices or drivers; and other tools and devices, which may be suitablefor surgery.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 illustrates a perspective view of a retractor assembly accordingto one embodiment;

FIGS. 2A-2D illustrate the components and a series of steps, which maybe used to install a pedicle screw in bone and mount a retractor bladethereto intra-operatively;

FIGS. 3A-3P provide addition detail on shims or screw mounts suitablefor use in attaching a pedicle screw to the retractor blade;

FIGS. 4A-4C show attachment of a retractor blade member to a pediclescrew according to another embodiment;

FIGS. 5A-5C show attachment of a retractor blade member to a pediclescrew according to yet another embodiment;

FIGS. 6A-6D depict an alternative attachment mechanism between a pediclescrew and a retractor blade;

FIGS. 7A-7C illustrate yet another attachment mechanism between apedicle screw and retractor blade; and

FIGS. 8A-8C show attachment of a retractor blade member to a pediclescrew according to another embodiment.

DETAILED DESCRIPTION

Embodiments of the disclosure are generally directed to devices,systems, kits, and methods for retraction and/or distraction using apedicle-based retraction system. Specifically, the pedicle-basedretractors include secure and reversible connections between the pediclescrew and retractor blade. The retractor blade may be attached to thescrew before or after the screw has been implanted in the bone. Whenattached intra-operatively, the attachment mechanism may minimize theamount of tissue disruption at the surgical site.

In a spinal fusion procedure, a damaged spinal disc may be removed andreplaced with an intervertebral implant (e.g., a cage, spacer, vertebralbody replacement, bone graft material, or other prosthetic). Theadjacent vertebrae may be stabilized, for example, with a combination ofscrews and rods. The operation may be performed in an open procedure,semi-open procedure, percutaneous, or in a minimally invasive surgical(MIS) procedure. As part of the procedure, a retractor may be used toestablish, enlarge, manipulate, and/or maintain a surgical opening,thereby facilitating the passage of the various implant devices andrelated tools. In some instances, different retractors may be used fordifferent surgical approaches (e.g., anterior, posterior,transforaminal, lateral), due to the varying anatomical features uniqueto each approach. The retractor blades may be used to hold back softtissue and muscle, and precise angling of the retractor's blades maydepend at least in part on various factors, including the particularpatient's anatomy and surgeon's preference.

Overall, retractor systems disclosed herein may advantageously provide ascrew-based retraction and distraction, resulting in more precise tissueretraction and distraction of adjacent bones. In particular, apedicle-based retraction system may include one or more retractor bladestemporarily affixed to one or more pedicle screws each configured toengage a pedicle of a vertebra. Once attached to a retractor body, theretractor blades and attached pedicles may retract soft tissue and/ormuscle and distract the disc space. Although described herein withregards to specific pedicle-based blade designs, those skilled in theart may appreciate that the blades described herein may be used in anysuitable retractor design.

As used herein, the terms “proximal” and “distal” are utilized generallywith reference to a user (e.g., a surgeon). When used with reference tothe retractor assembly, described further herein, the terms “lateral”and “medial” refer generally to the ends and the middle position,respectively. For example, a retractor arm traveling in a lateraldirection may be traveling from a middle portion outwardly, and aretractor arm traveling in a medial direction may be traveling from anend portion towards the middle. These and other directional terms suchas “top” and “bottom” and the like may be used herein for descriptivepurposes and do not limit the orientation(s) in which the devices may beused.

Some embodiments may include a two-bladed retractor. The retraction maybe controlled medially and laterally, for example. Each blade may alsohave a towing or pivoting capability. Although a two blade design isexemplified, it is understood that the retractor may encompass three ormore blades, four or more blades, or the like in order to provideretraction in the medial, lateral, cephalad, caudal, or otherorientations as may be desired.

The retractor system may include a variety of sub-components dimensionedto allow for retraction of soft tissue and/or muscle in order toestablish an operative corridor through a patient's skin to a surgicaltarget site as well as a screw-based component to allow for distractionof adjacent bones. By way of example, the surgical target site may be anintervertebral disc space situated between two adjacent vertebrae.Although particularly suited for use in a transforaminal lumbarinterbody fusion (TLIF), it will be readily appreciated by those skilledin the art that the retractor system may be employed in any number ofsuitable orthopedic approaches and procedures, including but not limitedto, anterior, posterior, lateral, anterolateral, or posterolateralapproaches to the lumbar spine, cervical spine, or thoracic spine, aswell as any non-spine application, such as treatment of bone fracturesand the like.

Turning now to the drawing, where like reference numerals refer to likeelements, FIG. 1 illustrates a retractor system 10. The retractor system10 includes a frame or base 12 that is attachable to an arm and/orsupporting structure (not shown). For example, the base 12 may bedirectly or indirectly attachable to a table, a rack, a cart, or thelike. In one embodiment, the base 12 is configured to be attached to asurgical arm, such as a universal arm, which includes enough joints toprovide a desired number of degrees of freedom to easily adjust the base12 over an incision in a patient. Preferably, the base 12 is configuredto be positioned in a substantially stationary position over thesurgical access site.

Broadly, the base 12 provides a scaffold to hold the various componentstogether and one or more mechanisms for operating the retraction and/ordistraction. In particular, the base 12 provides a mechanism to expandthe operative corridor by moving the retractor blades 20 toward or awayfrom one another. The base 12 may include one or more arms or posts 14configured to receive or attach to one or more blades 20 thereto. Eachpost 14 is configured to enable the retractor blades 20 to retractnearby soft tissue and/or distract a bone segment. The base 12 includesone or more knobs 16 configured to operate the retractor 10. Forexample, the knobs 16 may provide for movement of posts 14, therebyproviding for movement of the blades 20. Each of the respective knobs 16may provide for independent movement of each respective blade 20including lateral movement, medial movement, pivoting or towing or theblades 20, or the like as will be recognized by one of ordinary skill inthe art. Although one type of retractor 10 is exemplified herein, it isunderstood that any suitable retractors known in the art may be used.Further detail of such devices may be found, for example, in U.S. Pat.Nos. 8,852,090; 8,932,215; 8,968,363; and 8,992,425, which areincorporated by reference herein in their entireties for all purposes.

One or more blades 20 are removably coupled to the base 10. The positionof each retractor blade 20 can be changed independent from the otherretractor blades 20, which allows a great amount of flexibility to thesurgeon to explore an operating field. Furthermore, the position of eachretractor blade 20 can be changed without changing the position of thebase 10. Thus, the base 10 may remain in a substantially stationary andfixed position over the incision. In this regard, a change in theoperating field can be obtained by changing the position of the blades20.

In general, each retractor blade 20 has a first, proximal end portion 22configured to engage with the base 12, for example, having an opening toreceive post 14 and a second, distal end portion 24 configured toconnect with a screw member 30. Each blade also includes an inner face,an outer face, and a longitudinal axis running the length of the blade20 from the proximal end 22 to the opposite distal end 24. Differentblade geometries may be used based on the patient anatomy and surgeonpreference. For example, the blades 20 may be provided with a convexityat the proximal end 22 to cup under tissue and muscle to prevent theblades 20 and retractor from floating upward. In one embodiment, theretractor blades 20 have a curved or partial cylindrical shape, suchthat when blades 20 are aligned adjacent one another, a cylinder,channel, cannula, or the like is created therebetween. The size of theretractor blades 20 may dependent on the type of surgical procedure. Thetype, size, and shape of the surgical retractor blades 20 can be mixedtogether as well as changed or renewed during a surgical procedure.

The screw member 30 is configured to be removably attached to theretractor blade 20 as described in the various embodiment providedherein. The screw member 30 may include a head portion 32 (e.g., anenlarged head 32) at a proximal end configured to engage the retractorblade 20 and a shank or bone engagement portion 34 configured to engagebone, for example, having a taper at a distal end. The screw member 30may be centrally cannulated along a longitudinal length from theproximal end to the distal end of the screw member 30, for example, suchthat the screw member 30 may be guided over a k-wire or the like. Thescrew member 30 may be in the form of a pedicle screw 30 having athreaded portion configured to engage the pedicle in a vertebral body.The head portion 32 may also be threaded or non-threaded. The pediclescrew 30 may be configured to provide uni-planar, bi-planar, orpoly-axial orientation of the shank, for example. In the alternative,the screw member 30 may include any fixation members, such as nails,spikes, shims, or the like, which are known in the art.

With reference on FIGS. 2A-2D, a system and method for attaching apedicle screw member 30 to a blade 20 is provided. In particular, a shimor screw mount 40 connects the pedicle screw member 30 to the blade 20.The shim or screw mount 40 includes an extension portion 42 and a headportion 44. The extension portion 42 may include a track 46, forexample, in the form of one or more recesses and/or protrusionsextending along a longitudinal length of the extension portion 42. Thetrack 46 is configured to slidably engage and mate with a correspondingtrack portion 62 on a driver 60. The head portion 44 of the screw mount40 may be sized and configured to receive the head 32 from the screwmember 30. In particular, the head portion 44 may define an opening oraperture 48 configured to allow for side-loading of the screw member 30.The head portion 44 may house an internal sphere 50 within. The internalsphere 50 may be sized and configured to rotationally reside within thehead portion 44 of the screw mount 40. The internal sphere 50 may havean opening or aperture corresponding to aperture 48 in the head portion44, when in an unlocked position, such that the screw member 30 may beside loaded into the screw mount 40. The internal sphere 50 may berotated by driver 60 such that the aperture 48 of the head portion 44 issubstantially blocked, thereby locking the screw member 30 within thehead portion 44 of the screw mount 40 in a locked position.

The driver 60 may include a distal portion configured to engage thescrew mount 40 and a proximal portion configured to engage a handle (notshown) or other instrumentation to be manipulated by a user (e.g., asurgeon). For example, a quick connect handle may be attached to thedriver 60. The driver 60 may include an elongated outer shaft 66 havingan inner shaft 68 received longitudinally therethrough. The inner shaft68 may also be cannulated along its length, for example, to be guided bya k-wire or the like. The inner shaft 68 may be configured to rotatewith respect to the outer shaft 66. The inner shaft 68 may terminate ata distal tip 64. The distal tip 64 may have a hexalobular portion, forexample, which engages with a portion of the screw mount 40. The distaltip 64 may be of any suitable shape and configuration including, but notlimited to, round, triangular, squared, polygonal, star, torx,irregular, uniform, non-uniform, offset, staggered and/or tapered. Theouter shaft 66 may also include a track portion 62 extendinglongitudinally along a length of the driver 60. The track portion 62 maybe in the form of one or more extensions or recesses configured to matewith a corresponding track 46 on the screw mount 40.

A series of steps, which may be used to install the pedicle screw 30 inbone and mount a retractor blade 20 thereto is further described. Any ofthese steps may be performed before or during the operation in anysuitable order. The screw mounts 40 may be available as a kit or set,for example, in a caddy sitting upright (not shown), such that a usercan use driver 60 to select a screw mount 40. With reference on FIG. 2A,shown in step (a), the driver 60 may be pressed downward onto the screwmount 40. In particular, the distal tip 64 of the driver 60 may includean extension configured to engage a corresponding recess in the top ofthe head portion 44 of the screw mount 40 and/or a recess in the head 32of the screw member 30, for example, via a press-fit connection. Inaddition, the track portion 62 on the driver 60 may slidably engage thetrack 46 on the extension portion 42 of the screw mount 40. Thecorresponding and intermeshing tracks 46, 62 and press-fit connection ofthe tip 64 with head portion 44 may provide for visual, audible, and/ortactile feel when the driver 60 snaps onto the screw mount 40. The fullyseated screw mount 40 on driver 60 is shown in step (b). After verifyingthe connection, a thumb knob (not shown) on the driver 60 can beutilized to make sure that the internal sphere 50 of the screw mount 40is in the unlocked position (e.g., with apertures aligned to allow forside loading of the screw member 30).

As shown in step (c), the screw member 30 may be side-loaded into thescrew mount 40. The hexalobular portion of the inner shaft 68 of thedriver 60 may be pulled back and the screw head 32 inserted into thehead portion 44 of the screw mount 40 from the side. The resultingconstruct is shown in step (d) with the screw member 30 received inscrew mount 40 and attached to driver 60. The hexalobular portion of thedriver 60 may then be pushed forward and engaged with the screw 30 (notvisible).

Turning now to FIG. 2B, as shown in step (e), the internal sphere 50 inthe head portion 44 of the screw mount 40 may be rotated into the lockedposition. For example, a driver thumb knob may be rotated, for example,180 degrees, to turn the internal sphere 50 to the locked position. Aclose up view of the screw mount 40 in the unlocked positioned is shownin (e1) and (e2) shows a close up view of the screw mount 40 in thelocked position. A solid stop (not shown) may also be present to ensurethat the internal sphere 50 remains in the locked position.

At the surgical site, a Jamshidi needle and k-wire may be placed intothe pedicle. A series of cannulas may be inserted over the k-wire todilate the tissue and obtain the blade length. The cannulas may then beremoved, leaving the k-wire in place. The driver assembly, including thescrew member 30 and screw mount 40 connected to the driver 60, may passover the k-wire and the screw member 30 may be inserted into the pedicle(e.g., threaded into the pedicle).

Turning now to FIG. 2C, prior to disconnecting the driver 60 from thescrew mount 40, as shown in steps (f) and (g), the blade 20 may beengaged with the driver 60. As shown in step (h), the blade 20 may beslid down the side of the driver 60 and onto the screw mount 40. Inparticular, the blade 20 may also include a track configured to engagewith the track 62 on the outer shaft 66 of the driver and connect withan outer portion of the extension portion 42 of the screw mount 40.

As best seen in FIG. 2D, in steps (i) and (j), once the blade 20 hasbeen connected with the screw mount 40, the driver 60 can be removed.The series of driver assembly, screw insertion, blade insertion anddriver removal may be repeated at the other pedicle sites as many timesas necessary for the operation. Once the screws 30, screw mounts 40, andblades 20 are in place, as shown in step (k), the retractor body 10 canbe attached to the blades 20, for example, from a side approach. Asshown, the posts 14 can be positioned within openings in the blades 20.The blades 20, including the screw mounts 40 and screws 30, and thevertebral bodies attached thereto can now be manipulated by theretractor 10. For multi-level constructs, the retractor base 10 can beremoved from the blades 20 and the retractor 10 reattached to adjacentblades 20. If necessary, the blades 20 and/or screw mount 40 may berotated about the pedicle screw member 30 before the retractor 10 isreattached to adjacent blades 20.

After the interbody work has been completed, the same or a separatedriver 60 may be introduced to turn the internal sphere 50 into theunlocked position. The retractor blades 20 can be retracted out further,thereby separating the screw member 30 from the screw mounts 40. Thepedicle screws 30 can remain in the pedicles and can be used for aresulting fusion procedure (e.g., combined with rods). By moving theretractor blades 20 outward, this will allow enough space for screwtulips to be introduced and connected to the screw members 30. Afterrods and locking caps have been introduced, the retractor 10, blades 20,and screw mounts 40 may be removed, for example, at the same time.

FIGS. 3A-3P provide further details of shim or screw mount 40, which maybe used to connect blade 20 to screw 30, for example. The shim or screwmount 40 may include extension portion 42 and connection portion or headportion 44. The extension portion 42 may be in the form of an elongatedmember extending from a proximal end to a distal end. The extensionportion 42 may include track 46 along a front surface. The track 46 mayinclude one or more recesses or grooves extending along a longitudinallength of the extension portion 42. The track 46 is configured to engageand mate with a corresponding track portion 62 on driver 60.

The connection portion or head portion 44 of the screw mount 40 may bein the form of an outer spherical portion. The outer spherical portionof the head portion 44 may be generally rounded or spherical in shapeand may be generally hollow within. The head portion 44 is preferablysized and shaped to receive at least a portion of the head 32 of screwmember 30 therein. The head portion 44 preferably defines opening oraperture 48 in order to provide for side-loading of the screw member 30.The bottom of the head portion 44 also includes an opening configured toreceive a portion of the shaft of the screw 30. The head portion 44 maybe connected to the extension portion 42 at a distal end of theextension portion 42.

The head portion 44 preferably retains internal sphere 50 within. Theinternal sphere 50 may be sized and shaped to be retained within thehead portion 44 of the screw mount 40. The internal sphere 50 alsoincludes an opening configured to receive a portion of the shaft of thescrew 30. The internal sphere 50 is preferably configured to rotate withrespect to the head portion 44 of the screw mount 40. Internal sphere 50may extend through an opening in the top of the head portion 44 suchthat the internal sphere is able to engage with driver 60. The internalsphere 50 may have an opening or aperture corresponding to aperture 48in the head portion 44. FIGS. 3A-3C show an unlocked position of theinternal sphere 50 such that the side-opening in the internal sphere 50is aligned with the side-opening in the head portion 40. When unlocked,the screw member 30 may be side loaded into the screw mount 40.

FIGS. 3D-F depict screw mount 40 in a locked position (with the screw 30absent). In other words, the internal sphere 50 is rotated, for example,by driver 60, such that the aperture 48 of the head portion 44 issubstantially blocked by side wall 52 of the internal sphere 50, therebylocking the screw member 30 within the head portion 44 of the screwmount 40 in the locked position.

In one embodiment, only the inner sphere 50 is able to rotate. In analternative embodiment, the two spherical members 44, 50 are each ableto rotate independently of one another. Once the screw 30 is insertedinto the internal sphere 50, the internal sphere 50 is rotated, forexample, 180 degrees, to block the screw head 32 from being removed fromthe direction that it was inserted. The external sphere 44 contains thescrew 30 from being removed from the back side. A physical stop may beprovided to give the surgeon feedback to know when the internal sphere50 has been rotated to the locked position. A feature 54 on the top ofthe internal sphere 50 may be utilized to allow the driver 60 to matewith the sphere 50 and turn it. The feature 54 may include one or morerecesses and/or protrusion, for example, having a round, triangular,squared, polygonal, star, torx, irregular, uniform, non-uniform, offset,staggered and/or tapered shape configured to engage with the distal tip64 of the driver 60. The outer sphere 44 is retained by the retractorblade 20 to keep it from spinning with the inner sphere 50. The screw 30can retain its ability to rotate and pivot to a desired angle. Theinternal sphere 50 can be rotated, for example another 180 degrees, tounblock the screw 30 for removal from the screw mount 40.

As shown in FIGS. 3G-3P, the steps for inserting screw 30 are shown forside-loading the screw 30 into the mount 40. In FIGS. 3G and 31, thehead 32 of the screw 30 is aligned with the opening 48 in the outersphere 44. The inner sphere 50 is in the unlocked position. In FIGS. 3Hand 3J, the head 32 of the screw is inserted in the inner sphere 50 thatis positioned inside the outer sphere 44. FIGS. 3K-3M show driver 60engaging the top of inner sphere 50. FIGS. 3N-3P show the inner sphere50 rotated to the locked position such that the side wall 52 of theinner sphere 50 blocks the aperture 48 of the outer sphere 44.

Turning now to FIGS. 4A-4C, another mechanism of attachment between theretractor blade 120 and the pedicle screw 130 is shown. In particular,FIG. 4A depicts a front view of the blade assembly 100 including screwmount or shim 140 connecting the pedicle screw 130 to the retractorblade 120. In this design, the screw mount or shim 140 wraps around theouter edges of the blade 120 to keep it in place. FIG. 4B depicts a sideview of an edge 142 of the shim 140 engaged with the blade 120. Theblade 120 extends from a proximal end portion 122 to a distal endportion 124 configured to engage with and retract soft tissues and/ormuscle. The blade 120 has a generally curved inner portion configure tomate with a generally curved portion of the shim 140. The blade 120includes two extensions or end portions 118 at the outer most portionsof the curved blade. These end portions 118 may extend along a portionor an entire length of the blade 120 from the proximal end 122 to thedistal end 124. The shim 114 includes extension portions with edges 142configured to surround the end portions 118 of the blade 120. FIG. 4Cshows a top view of the assembly 100.

When installing the assembly 100 or a portion thereof, the bone screw130 may be threaded in to the pedicle and the screw mount 140 may beadded before or after the bone screw 130 is engaged with the pedicle.With the bone screw 130 and shim 140 in place, the retractor blade 120slides into the shim 140. One or more locks 126 (e.g., two locks 126shown in FIG. 4A) may be provided on the outer edges or end portions 118of the blade 120 such that the locks 126 engage once the screw 130 isfully engaged inside the bone. One or more stops 128 (e.g., two stops128 shown in FIG. 4A) may also be provided on the blade 120 at thedistal end 124 to prevent the shim 140 from backing out proximallyduring the surgery. A removal slot and/or tab 152 may be operable by aremoval tool to disengage the distal end of the shim 140 from the headof the screw 130, thereby allowing the shim 140 to slide back up theouter edges of the blade 120 and separate from the blade 120.

FIGS. 5A-5C depict an alternative version of a blade assembly 200 wherethe screw mount or shim 240 engages interior rails 216 on the blade 220.In FIG. 5A, a front view of the blade assembly 200 is shown includingscrew mount or shim 240 connecting the pedicle screw 230 to theretractor blade 220. In this design, the shim 240 slides down theinterior rails 216 of the blade 220 to keep the shim 240 in place. FIG.5B depicts a side view of the shim 240 engaged with the blade 220. Theblade 220 extends from a proximal end portion 222 to a distal endportion 224 configured to engage with and retract soft tissues. In oneembodiment, the blade 220 is identical to blade 120 such that shim 240and shim 140 are interchangeable with the same blade 120, 220 design.One or more locks 226 (e.g., two locks 226 shown in FIG. 5A) may beprovided on the outer edges or end portions of the blade 220, forexample, if shim 140 where selected.

The blade 220 may have a generally curved inner portion having one ormore rails 216, for example, in the form of channels or grooves, definedalong a portion or an entire length of the blade 220 from the proximalend 222 to the distal end 224. The shim 214 includes corresponding rails246, for example, in the form of ridges or tongues, configured to bereceived within and slidably engage the rails 216 of the blade 220. FIG.5C shows a top view of the assembly 200. The shim 214 also includes apartial or complete ring 244 configured to at least partially surroundor rest below the head portion 242 of the screw 230. As the bone screw230 is driven into the pedicle, one or more dimples may be centeredinside the rails 216 (e.g., the outer two rails 216) of the blade 220that engage with the shim 240 while the screw 230 is being driven intothe bone. A removal tool can be used to allow the shim 240 to slide backup the rails 216 and separate from the blade 220.

Turning now to FIGS. 6A-6D, another mechanism of attachment between theretractor blade 220 and the pedicle screw 330 is shown. In particular,FIG. 6A depicts a front view of the blade assembly 300 including screwmount or rotating shim 340 connecting the pedicle screw 330 to theretractor blade 320. In this design, the shim 340 is configured torotate or spin in order to catch and lock or unlock the pedicle screw330 to the blade 220.

The blade 220 may have a generally curved inner portion having one ormore rails 316, for example, in the form of channels or grooves, definedalong a portion or an entire length of the blade 320. Similar toassembly 200, the shim 340 may be configured to slide down the interiorrail 316 of the blade 320 to keep the shim 340 in place. In this case,the rail 316 may be a single, central rail 316 in the form of aninternal T-slot, for example. The shim 314 includes a corresponding rail346, for example, in the form of a ridge or tongue, configured to bereceived within and slidably engage the rail 316 of the blade 320. Inparticular, the shim 314 may include a single, central T-rail 346. FIG.6D shows a top view of the assembly 300. The shim 314 also includes apartial ring 344 configured to at least partially surround or restbeneath the head portion 342 of the screw 330. The ring 344 includes anopening to allow for side loading of the screw 330 onto the shim 340.

The pedicle screw 330 may be inserted into the pedicle, for example,using an open or MIS approach. The rotating shim 340 may be insertedinto the retractor blade 320 via the internal T-slot 316 and T-rail 346.The rotating shim 340 can be locked in place using one or more dimples,for example. With the shim 340 inserted, the retractor blade 320 andshim 340 can be inserted into the incision and moved (e.g., cephaladand/or caudal) until the shim 340 hooks onto the pedicle screw 330. Theshim 340 may or may not lock to the screw 330. Once attached for allpedicles, the blades 320 may be attached to the retractor body. Todisconnect the shim 340 from the screw 330, a tool (e.g., a hex tool)may be configured to rotate the shim 340 (e.g., 180°) while still in theblade 320, thereby allowing for the blades to be retracted further(e.g., cephalad and/or caudal) without being attached to the pediclescrews 330 any further.

FIGS. 7A-7C depict assembly 400 including retractor blade 420, shim 440,and pedicle screw 430. In this embodiment, the shim 440 is in the formof a split collet. For example, the shim 440 may include two separatearms separated by a longitudinal slot having a ring 444 at a distal-mostend. A slight interference between the collet 440 and screw head 432allows the shim 440 to be clicked over the shank of the screw 430. Theshim 440 may snap over the screw head 432 and be inserted through theincision with the pedicle screw 430. Once the screw 430 is in place, theretractor blade 420 may be inserted and slid over the shim 440 using aninternal T-slot similar to that described in assembly 300. There may beno secondary locking between the screw 430 and the shim 440 andretractor blade 420. Alternatively, there may be an extended groove orslot 448 for addition tightening. As best seen in FIG. 7B, as theretractor blades 420 slides down, there is an elongated slot 448 in theshim interference causing the collet 440 to tighten further, therebybetter locking screw 430 to the shim 440. With the blades 420 connectedto the shims 440 and screws 420, the retractor can be attached to theretractor blades 420. To remove the shim 440, a separate tool can beused to loosen the connection between the shims 440 and the screw 430 toremove the shim 440 from the retractor blade 420.

FIGS. 8A-8C illustrate an alternative embodiment for attachment betweenthe pedicle screw 530 and the blade 520. In this embodiment, the screw530 is directly attached to the blade 520 using a wire, filament, fiber,or cable 540. The cable 540 may include any suitable elongate elementconfigured to engage the pedicle screw and the blade 520 at one or morepoints of contact. For example, the retractor blade 520 may have thecable 540 attached on one end, for example, at the top of the blade 520.The cable 540 may be routed down the blade tip where it will form a hoopand be routed back up to the top of the blade 520. The cable 540 mayextend through one or more openings in the blade 520, for example. Theshank of the screw 530 may be threaded into the pedicle using a driver,for example. Prior to removing the driver, a slackened hoop of cable 540may be placed around the driver and the blade 520 may be inserted downthe incision using the driver as a guide. Once the retractor blade 520reaches its predetermined depth, the cable 540 can be tightened, forexample, using one or more thumb knobs 550, thereby taking up the slackand tightening the cable 540 around the screw 530. Thumb knobs 550 maybe in the form of wheels or cylinders, for example, attached to theproximal end of the blade 520. The thumb knobs 550 may be configured torotate such that the cable 540 winds around the base of the knobs 550.The driver can then be detached and removed from the incision. Ifneeded, distraction of the disc space can take place, for example, usingthe pedicle screws 530. To remove the retractor blade 520 from the screw530 after the retraction is no longer needed, the cable 540 can beslacked again or disconnected entirely from one or both ends. As theblades 520 are removed, the cable 540 can unwind and pull free from thescrew 530.

Components of all of the devices disclosed herein can be made ofmaterials known to those skilled in the art, including metals (e.g.,titanium), metal alloys (e.g., stainless steel, cobalt-chromium, andtitanium alloys), ceramics, polymers (e.g., polyether ether ketone(PEEK), polyphenylene sulfone (PPSU), polysulfone (PSU), polycarbonate(PC), polyetherimide (PEI), polypropylene (PP), polyacetals, or mixturesor co-polymers thereof), allograft, and/or combinations thereof. In someembodiments, the devices may include radiolucent and/or radiopaquematerials. The components can also be machined and/or manufactured usingtechniques known to those skilled in the art.

Advantageously, the blades, retractor systems, and associated devicesdescribed herein can be used with a number of different implants anddevices. For example, the retractor systems and devices can be used toprovide access to a surgical site such that a device that preservesmotion can be provided. In addition, the retractor systems and devicescan be used to provide access to a surgical site such that a fusiondevice, such as a cage or spacer, or standalone device, can be provided.In addition, the retractor systems and devices can be used to provideaccess to various other devices, including but not limited to rods,screws (e.g., pedicle screws, cortical screws, etc.), plates and variousother implants that are used in spine surgery.

As described herein, the specially designed connections between thepedicle screw and retractor blade provide for improved pedicle-basedretraction and distraction. The connections create a secure reversibleconnection between the pedicle screw and the retractor blade. Theconnections can be made before or during the operation, and if insertedintra-operatively, the blade may be attached to and removed from thescrew in a manner to minimize the amount of tissue disruption at thesurgical site.

Although the invention has been described in detail and with referenceto specific embodiments, it will be apparent to one skilled in the artthat various changes and modifications can be made without departingfrom the spirit and scope of the invention. Thus, it is intended thatthe invention covers the modifications and variations of this inventionprovided they come within the scope of the appended claims and theirequivalents. It is expressly intended, for example, that all rangesbroadly recited in this document include within their scope all narrowerranges which fall within the broader ranges. It is also intended thatthe components of the various devices disclosed above may be combined ormodified in any suitable configuration.

What is claimed is:
 1. A method of retracting and distracting a discspace between first and second vertebrae, the method comprising:providing a retractor assembly comprising: a retractor body; a firstretractor blade having a proximal end configured to engage the retractorbody and a distal end configured to retract soft tissue; a first pediclescrew having a head portion removably connectable to the distal end ofthe first retractor blade and a shaft portion configured to engage bone;and a first shim having an extension portion, an outer sphericalportion, and an inner spherical portion rotatably received within theouter spherical portion, wherein the extension portion is configured toengage the first retractor blade and the inner spherical portion isconfigured to receive the head portion of the first pedicle screw,wherein the inner spherical portion rotates from an unlocked position toa locked position for retaining the head portion of the first pediclescrew within the first shim; connecting a driver to the first shim;attaching the first pedicle screw to the first shim by side loading thefirst pedicle screw into the first shim and locking the first pediclescrew to the first shim; attaching the first pedicle screw to a pedicleof the first vertebra; sliding the first retractor blade having aproximal portion and a distal portion down the driver and onto the firstshim such that the distal portion of the first retractor blade connectsto the first shim; removing the driver; and connecting the retractorbody to the proximal portion of the first retractor blade.
 2. The methodof claim 1 further comprising: connecting the driver to a second shim;attaching a second pedicle screw to the second shim by side loading thesecond pedicle screw into the second shim and locking the second pediclescrew to the second shim; attaching the second pedicle screw to apedicle of the second vertebra; sliding a second retractor blade havinga proximal portion and a distal portion down the driver and onto thesecond shim such that the distal portion of the second retractor bladeconnects to the second shim; removing the driver; connecting theretractor body to the proximal portion of the second retractor blade;and retracting and distracting the disc space using the first and secondretractor blades and the first and second pedicle screws, respectively.3. The method of claim 1, wherein the extension portion includes atleast one rail configured to slidably engage at least one correspondingrail on the first retractor blade.
 4. The method of claim 1, wherein theextension portion includes at least one edge configured to surround oneor both end of the first retractor blade.
 5. The method of claim 1,wherein the first retractor blade includes a generally curved innerportion having one or more grooves defined along at least a portion ofthe first retractor blade, the one or more grooves configured toslidably engage one or more corresponding tongues of the extensionportion of the first shim.
 6. The method of claim 1, wherein a topportion of the inner spherical portion extends through an opening in theouter spherical portion, and the top portion is configured to be engagedby the driver in order to rotate the inner spherical portion from theunlocked position to the locked position.
 7. The method of claim 1,wherein the outer spherical portion and the inner spherical portion eachinclude an opening that, when aligned, allow the first pedicle screw tobe side-loaded into the shim.
 8. The method of claim 1, wherein thefirst pedicle screw is configured to polyaxially rotate in the firstshim.
 9. The method of claim 1, wherein the driver includes at least onetrack configured to engage at least one rail on the extension portion ofthe first shim.
 10. A method of retracting and distracting a disc spacebetween first and second vertebrae, the method comprising: providing aretractor blade assembly comprising: a retractor blade having a proximalend configured to engage a retractor body and a distal end configured toretract soft tissue; a screw having a head portion removably connectableto the distal end of the retractor blade and a shaft portion configuredto engage bone; and a shim having an extension portion and a connectionportion, wherein the extension portion is configured to engage theretractor blade and the connection portion is configured to receive atleast a portion of the screw, wherein the connection portion is movablefrom an unlocked position to a locked position for retaining the screwwithin the shim, wherein the connection portion includes an outerspherical portion and an inner spherical portion, a top portion of theinner spherical portion extends through an opening in the outerspherical portion, and the top portion is configured to be engaged by adriver in order to rotate the inner spherical portion from the unlockedposition to the locked position attaching the screw to the shim by sideloading the screw into the shim and locking the screw to the shim;attaching the screw to a pedicle of the first vertebra; sliding theretractor blade having a proximal portion and a distal portion down thedriver and onto the shim such that the distal portion of the firstretractor blade connects to the shim; removing the driver; andconnecting a retractor body to the proximal portion of the retractorblade.
 11. The method of claim 10, wherein the extension portionincludes at least one rail configured to slidably engage at least onecorresponding rail on the retractor blade.
 12. The method of claim 10,wherein the extension portion includes at least one edge configured tosurround one or both end portions of the retractor blade.
 13. The methodof claim 10, wherein the retractor blade includes a generally curvedinner portion having one or more grooves defined along at least aportion of the retractor blade, the one or more grooves configured toslidably engage one or more corresponding tongues of the extensionportion of the shim.
 14. The method of claim 10, wherein the connectionportion is configured to rotate relative to the retractor blade.
 15. Themethod of claim 10, wherein the shim includes an elongated slotextending longitudinally along a length of the shim.
 16. The method ofclaim 10, wherein the connection portion includes at least a partialring configured to at least partially surround the head portion of thescrew.
 17. The method of claim 10, wherein one or more locks arepositioned along one or both outer edges of the retractor blade toprevent the shim from sliding off the retractor blade.